Once upon a time
in the village of Nishikubo, Chigasaki in Kanagawa prefecture, there lived a grandpa called Gorobei 五郎兵衛 with his horse. The horse leader 馬方 Gorobei liked to drink sake quite a lot and the horse and his sake flask were the most precious things in his live.

One evening in summer, after his work was finished, he went down to the river to wash his horse. But a Kappa came up and began to bite into his horse, trying to pull it into the deep water. When Gorobei saw his horse slowly disappearing in the water, he called out loud for the other villagers to help.

They fought the Kappa, freed the horse and bound the Kappa to a tree.
The Kappa pleaded:
"I have a wife and children in the river. Please, do not kill me, please, please!"

Gorobei was a kind-hearted man and so they let the Kappa go back to the river.

That evening, when Gorobei was back home, the Kappa came to his door with a sake flask. It was one of a kind, you could drink and drink and it would never get empty. If it felt empty, all you had to do was hit the bottom of the flask three times and it would fill up again in no time.

Gorobei was very happy with this new sake flask. He did not go back to work and spent day and night drinking, drinking, drinking his beloved rice wine. He even forgot to feed his horse and became quite a lazy fellow.

One day when he was lying down drunk at his doorstep, he saw the pour horse, which had lost all its weight and energy. He felt a great remorse and reconsidered his drinking habit. Then he hit the bottom of his magic tokkuri three times and promised, never to have a drop come out of it again, never to drink sake again.

This was just in time to prevent him from becoming really dependent on his drinking. Now he was cured of his addiction and became the brave horse leader he was before.
And the magic tokkuri is still in the possesion of a home in Nishikubo.- source : nihon.syoukoukai.com